Couplings for connecting fluid lines are well known and include a coupler socket (female half) and a nipple (male half). In some types of couplings, when the male half is inserted into the female half, a valve assembly in the female half opens to provide a flow path through the coupling. At the same time, a catch or coupling mechanism automatically engages the male half to retain the male half within the female half. Typically, the coupling mechanism can be manually released to disconnect the male half from the female half, at which point the valve assembly closes the flow path. Such a coupling is conventionally referred to as a "push-to-connect" coupling.
The male half of a coupling typically includes tubular valving or plug circumscribing a central passage, and a threaded fitting portion at its rear end which enables the male half to be connected to the pipe or tube. A valve assembly may also be provided in the male half. The valving of the male half narrows down at its forward end and includes an outwardly-facing circumferential groove or channel. When the male half is inserted into the female half, the coupling mechanism on the female half engages the groove on the valving to retain the male half within the female half.
One particularly useful type of push-to-connect coupling is referred to as a "flush face" coupling. In a flush face coupling, the front of the male half has a complimentary surface with the front of the female half such that the engaging surfaces of the male and female half are all flush with one another when connected. This flush face assembly is intended to prevent contaminants entering the coupler during connection and disconnection.
A number of different types of coupler sockets have been developed for receiving a male half. One known type of socket includes a cylindrical body with an internal, spring-biased poppet valve. The body of the female half has a series of tapered openings in a circumferential arrangement near the forward end, and a series of locking balls are received in the openings. A spring-biased locking collar is slidably disposed around the coupler body, and when the male valving is inserted into the socket, the locking collar forces the locking balls radially inward into the groove in the male half to lock the male half to the female half. At the same time, the poppet valve in the female half engages with a valve assembly in the male half to open a flow passage through the coupling.
To uncouple the male half from the female half, the locking collar is moved rearwardly, which allows the locking balls to move outwardly from engagement with the groove in the male half, and thereby allow the male half to be removed from the female half. As the male half is removed, the poppet valve in the female half and the valve assembly in the male half are moved to closed positions to prevent fluid flow through the respective halves of the coupling. French Patent Reference No. 1.577.931 shows such a flush-face, push-to-connect coupling.
In some applications, such as agricultural tractor applications, it can be necessary or desirable to have the coupling automatically disconnect under certain conditions, such as if an operator fails to disconnect the coupling before the tractor is driven away from an attached implement. To accomplish this breakaway feature, the locking collar of the female half of the coupling has been rigidly mounted to the tractor. When the male half is pulled away from the female half, the female body moves inside the locking collar and the coupling halves automatically disconnect.
While this solution may be appropriate for certain applications, it requires additional hose or tube to connect the female coupling body to the tractor. This increases the material, assembly and repair costs. In addition, this coupling does not allow for automatic disconnect when the pressure within the coupling increases above a predetermined amount. It can be useful or desirable to have the coupling automatically disconnect when a maximum pressure in the fluid system is reached. Still further, the male half can only be removed from the female half by pulling on the male half. This does not allow for conventional disconnect, where the operator manually moves the locking collar rearward on the coupling body to allow the male half to be disconnected.
It is therefore believed there is a demand for a further improved push-to-connect coupling which overcomes the above-described drawbacks.